Django 之组合搜索

系统管理员 2023-06-02 10:53 26阅读 0赞

现在很多网站都会有这样的组合搜索功能，其实质是几个模型之间组合对数据库进行查询，并将结果显示到页面上。

每一行都是一个模型，模型之间有着连表关系（一对多、多对多等）

![20190305150008.png][]

# 模型设计 #

*  总共四个模型：分别为方向、分类、等级以及存储结果信息
 *  一个方向下可以有多个分类，一个分类也可以是多个方向（多对多）
 *  一个分类可以有多个视频（一对多）
 *  一个等级下也可以有多个视频（一对多）

from django.db import models
    
    
    class Direction(models.Model):
        """方向：自动化、测试、运维、前端"""
        name = models.CharField(verbose_name='名称', max_length=32)
        classification = models.ManyToManyField('Classification')
    
        class Meta:
            db_table = 'Direction'
            verbose_name_plural = '方向（视频方向）'        # 模型的复数形式，若不指定则在后面加一个 s
    
        def __str__(self):
            return self.name
    
    
    class Classification(models.Model):
        """分类：Python、Linux、JavaScript、OpenStack、Node.js、C"""
        name = models.CharField(verbose_name='名称', max_length=32)
    
        class Meta:
            db_table = 'Classification'
            verbose_name_plural = '分类（视频分类）'
    
        def __str__(self):
            return self.name
    
    
    class Level(models.Model):
        """等级：初级、中级、高级、骨灰级"""
        title = models.CharField(max_length=32)
    
        class Meta:
            verbose_name_plural = '难度级别'
    
        def __str__(self):
            return self.title
    
    
    class Video(models.Model):
        status_choice = (
            (1, '下线'),
            (2, '上线'),
        )
    
        status = models.IntegerField(verbose_name='状态', choices=status_choice, default=1)
        level = models.ForeignKey('Level', on_delete=models.CASCADE)
        classification = models.ForeignKey('Classification', null=True, blank=True, on_delete=models.CASCADE)
    
        weight = models.IntegerField(verbose_name='权重（从大到小排列）', default=0)
    
        title = models.CharField(verbose_name='标题', max_length=32)
        summary = models.CharField(verbose_name='简介', max_length=100)
    
        # 也可以用 ImgField 或 FileField 存储图片，而不是 CharField，但是要指定存储路径
        # img = models.ImgField(verbose_name='图片', upload_to='app/static/app/video')
        img = models.CharField(verbose_name='图片', max_length=200)
        href = models.CharField(verbose_name='视频地址', max_length=256)
    
        create_data = models.DateTimeField(auto_now_add=True)
    
        class Meta:
            db_table = 'Video'
            verbose_name_plural = '视频'
    
        def __str__(self):
            return self.title

# URlconf 配置 #

urlconf 配置采用的是二级路由，即应用本身创建 `urls.py`：

# project/urls.py
    from django.contrib import admin
    from django.urls import path, include
    
    urlpatterns = [
        path('admin/', admin.site.urls),
        path('app/', include('app.urls')),
    ]
    
    # app/urls.py
    from django.urls import path
    from app import views
    
    urlpatterns = [
        path('video/<int:classification_id>/<int:level_id>/<int:status>/', views.video, name='video'),
        path('video2/<int:direction_id>/<int:classification_id>/<int:level_id>/', views.video2, name='video2'),
    ]

# 一对多 #

一对多关系中主要是视频信息与分类、等级之间的关系操作。

## 视图函数 ##

函数接收三个额外参数，分别为：分类 `classification` id、等级 `level` id 以及状态 `status` id。根据这三个参数构造查询条件（`filter()` 函数本身是支持字典形式查询的）。

> **Tips**

`condition` 构造的查询条件是字典形式，其键 `key`应与数据表中相应字段对应，如： `classification_id` 为模型 `Video`与 `Classification` 的外键字段名。

from django.shortcuts import render, HttpResponse
    from app.models import Level, Classification, Direction, Video
    
    
    def video(request, *args, **kwargs):
        print(args, kwargs)     # () {'classification_id': 1, 'level_id': 2}
    
    # 构造查询条件
        condition = {
            # 'classification_id': 0,
            # 'level_id': 0
        }
    
        # 当 kwargs = {'classification_id': 0, 'level_id': 0} 时，condition = {}，
        # Video.objects.filter(**condition) 能把所有的都查出来
        # 当 kwargs = {'classification_id': 1, 'level_id': 1} 时，condition = {'classification_id': 1, 'level_id': 1}
        # filter() 支持字典格式
        # 将其转换为整数
        for k, v in kwargs.items():
            temp = int(v)
            kwargs[k] = temp
            if temp:
                condition[k] = temp
    
        class_list = Classification.objects.all()
        level_list = Level.objects.all()
    
        # 查询数据
        video_list = Video.objects.filter(**condition)
    
        """
           status_choice = (
               (1, '下线'),
               (2, '上线'),
           )
           """
        # status_list：[{'id': 1, 'name': '下线'}, {'id': 2, 'name': '上线'}]
        status_list = list(map(lambda x: {'id': x[0], 'name': x[1]}, Video.status_choice))
    
        return render(
            request,
            'app/video.html',
            {
                'kwargs': kwargs,
                'class_list': class_list,
                'level_list': level_list,
                'video_list': video_list,
                'status_list': status_list
            }
        )

## 模板 ##

{% load static %}
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>视频</title>
        <style type="text/css">
            .box1 a{
                display: inline-block;
                padding: 5px 8px;
                border: 1px solid #dddddd;
            }
    
            .box1 a.active{
                background-color: coral;
                color: white;
            }
    
        </style>
    </head>
    <body>
        <div class="box1">
            <h1>筛选</h1>
            
            <div>
                {% if kwargs.classification_id == 0 %}
                    <a class="active" href="/app/video/0/{
         { kwargs.level_id }}/{
         { kwargs.status }}">全部</a>
                {% else %}
                    <a href="/app/video/0/{
         { kwargs.level_id }}/{
         { kwargs.status }}">全部</a>
                {% endif %}
    
                {% for class in class_list %}
                    {% if class.id == kwargs.classification_id %}
                        <a href="/app/video/{
         { class.id }}/{
         { kwargs.level_id }}/{
         { kwargs.status }}" class="active">{
         { class.name }}</a>
    
                    {% else %}
                        <a href="/app/video/{
         { class.id }}/{
         { kwargs.level_id }}/{
         { kwargs.status }}">{
         { class.name }}</a>
                    {% endif %}
    
                {% endfor %}
    
            </div>
    
    
            
            <div>
                {% if kwargs.level_id == 0 %}
                    <a href="/app/video/{
         { kwargs.classification_id }}/0/{
         { kwargs.status }}" class="active">全部</a>
                {% else %}
                    <a href="/app/video/{
         { kwargs.classification_id }}/0/{
         { kwargs.status }}">全部</a>
                {% endif %}
    
                {% for level in level_list %}
                    {% if level.id == kwargs.level_id %}
                        <a href="/app/video/{
         { kwargs.classification_id }}/{
         { level.id }}/{
         { kwargs.status }}" class="active">{
         { level.title }}</a>
                    {% else %}
                        <a href="/app/video/{
         { kwargs.classification_id }}/{
         { level.id }}/{
         { kwargs.status }}">{
         { level.title }}</a>
                    {% endif %}
                {% endfor %}
    
            </div>
    
            
            <div>
                {% if kwargs.status == 0 %}
                    <a href="/app/video/{
         { kwargs.classification_id }}/{
         { kwargs.level_id }}/0" class="active">全部</a>
                {% else %}
                    <a href="/app/video/{
         { kwargs.classification_id }}/{
         { kwargs.level_id }}/0">全部</a>
                {% endif %}
    
                {% for status in status_list %}
                    {% if status.id == kwargs.status %}
                        <a href="/app/video/{
         { kwargs.classification_id }}/{
         { kwargs.level_id }}/{
         { status.id }}" class="active">{
         { status.name }}</a>
                    {% else %}
                        <a href="/app/video/{
         { kwargs.classification_id }}/{
         { kwargs.level_id }}/{
         { status.id }}">{
         { status.name }}</a>
                    {% endif %}
                {% endfor %}
                
            </div>
        </div>
    
        <div>
            <h1>结果</h1>
            <div>
                {% for video in video_list %}
                    <p>{
         { video.title }}</p>
                    <img src="{
         { video.href }}">
                {% endfor %}
    
            </div>
        </div>
    
    </body>
    </html>

![20190305150008.png][]

# 多对多 #

多对多关系中主要是方向与分类之间的关系操作。

## 视图函数 ##

from django.shortcuts import render, HttpResponse
    from app.models import Level, Classification, Direction, Video
    
    def video2(request, *args, **kwargs):
        """
        多对多："方向-分类
        方向：自动化、测试、运维、前端
        分类：Python、Linux、JavaScript、OpenStack、Node.js、C
        等级：初级、中级、高级、骨灰级
        """
        print(kwargs)       # {'direction_id': 1, 'classification_id': 4, 'level_id': 2}
        direction_id = kwargs.get('direction_id')
        classification_id = kwargs.get('classification_id')
        level_id = kwargs.get('level_id')
        condition = {}      # 条件    构造查询字典
    
        # 方向：全部列举
        direction_list = Direction.objects.all()
    
        # 若方向为 0，则分类显示全部
        if direction_id == 0:
            # 若分类也为 0，分类显示全部
            class_list = Classification.objects.all()
            if classification_id == 0:
                pass
            else:
                condition['classification_id'] = classification_id
    
        # 若方向不为 0，则根据方向查询分类
        else:
            direction_obj = Direction.objects.filter(id=direction_id)[0]
            class_list = direction_obj.classification.all()     # 根据多对多名字+方向的ID，获取相应分类列表
            # < QuerySet[ < Classification: Python >, < Classification: Linux >] >
    
            # 根据方向 id 获取分类的 id 列表
            vlist = direction_obj.classification.all().values_list('id')   #  < QuerySet[(1,), (5,)] >
    
            # 若哪个方向下没有分类
            if not vlist:
                classification_id_list = []
            else:
                # 转换为元组
                classification_id_list = list(zip(*vlist))[0]       # (1, 5)
    
    
            # 若分类为 0，则显示相应分类
            if classification_id == 0:
                condition['classification_id__in'] = classification_id_list
            else:
                if classification_id in classification_id_list:
                    condition['classification_id'] = classification_id
                else:
                    condition['classification_id__in'] = classification_id_list
    
        if level_id == 0:
            pass
        else:
            condition['level_id'] = level_id
    
        # 等级：全部列举
        level_list = Level.objects.all()
        video_list = Video.objects.filter(**condition)
    
        return render(
            request,
            'app/video2.html',
            {
                'direction_list': direction_list,
                'level_list': level_list,
                'kwargs': kwargs,
                'video_list': video_list,
                'class_list': class_list
            }
        )

## 模板 ##

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>多对多和一对多</title>
        <style type="text/css">
            .box1 a {
                display: inline-block;
                padding: 5px 8px;
                border: 1px solid #dddddd;
            }
    
            .box1 a.active {
                background-color: coral;
                color: white;
            }
        </style>
    </head>
    <body>
        <div class="box1">
            <h1>筛选</h1>
            
            <div>
                {% if kwargs.direction_id == 0  %}
                    <a class="active" href="{% url 'video2' direction_id=0 classification_id=kwargs.classification_id level_id=kwargs.level_id %}">全部</a>
                {% else %}
                    <a href="{% url 'video2' direction_id=0 classification_id=kwargs.classification_id level_id=kwargs.level_id %}">全部</a>
                {% endif %}
    
                {% for direction in direction_list %}
                    {% if direction.id == kwargs.direction_id %}
                        <a href="{% url 'video2' direction_id=direction.id classification_id=kwargs.classification_id level_id=kwargs.level_id %}" class="active">{
         { direction.name }}</a>
                    {% else %}
                        <a href="{% url 'video2' direction_id=direction.id classification_id=kwargs.classification_id level_id=kwargs.level_id %}">{
         { direction.name }}</a>
                    {% endif %}
                {% endfor %}
    
            </div>
    
            
            <div>
                {% if kwargs.classification_id == 0 %}
                    <a class="active" href="{% url 'video2' direction_id=kwargs.direction_id classification_id=0 level_id=kwargs.level_id %}">全部</a>
                {% else %}
                    <a href="{% url 'video2' direction_id=kwargs.direction_id classification_id=0 level_id=kwargs.level_id %}">全部</a>
                {% endif %}
    
                {% for class in class_list %}
                    {% if class.id == kwargs.classification_id %}
                        <a class="active" href="{% url 'video2' direction_id=kwargs.direction_id classification_id=class.id level_id=kwargs.level_id %}">{
         { class.name }}</a>
                    {% else %}
                        <a href="{% url 'video2' direction_id=kwargs.direction_id classification_id=class.id level_id=kwargs.level_id %}">{
         { class.name }}</a>
                    {% endif %}
                {% endfor %}
    
            </div>
    
            
            <div>
                {% if kwargs.level_id == 0 %}
                    <a class="active" href="{% url 'video2' direction_id=kwargs.direction_id classification_id=kwargs.classification_id level_id=0 %}">全部</a>
                {% else %}
                    <a href="{% url 'video2' direction_id=kwargs.direction_id classification_id=kwargs.classification_id level_id=0 %}">全部</a>
                {% endif %}
    
                {% for level in level_list %}
                    {% if level.id == kwargs.level_id %}
                        <a class="active" href="{% url 'video2' direction_id=kwargs.direction_id classification_id=kwargs.classification_id level_id=level.id %}">{
         { level.title }}</a>
                    {% else %}
                        <a href="{% url 'video2' direction_id=kwargs.direction_id classification_id=kwargs.classification_id level_id=level.id %}">{
         { level.title }}</a>
                    {% endif %}
                {% endfor %}
            </div>
        </div>
    
    
        <div>
            <h1>结果</h1>
            {% for video in video_list %}
                <p>{
         { video.title }}</p>
            {% endfor %}
        </div>
    </body>
    </html>

![20190305150328.png][]

**参考博客**

*  [Django之组合查询][Django]
 *  [django实现瀑布流、组合搜索、阶梯评论、验证码][django]

转载于:https://www.cnblogs.com/midworld/p/11380491.html

[20190305150008.png]: /images/20230601/da7ba1bcc38c46f2bea72814aa410b33.png
[20190305150328.png]: /images/20230601/fb80a49ed0bf4323898d9abce9c267d4.png
[Django]: https://www.cnblogs.com/wuxunyan/p/9242710.html
[django]: https://www.cnblogs.com/pycode/articles/django3.html